Thermal Characterization of Innovative Sustainable Building Materials from Wool Textile Fibers Waste

Abstract

In the textile sector, fabrics produce waste from the earliest stages of production, particularly during the garment manufacturing process. The reuse of these materials as byproduct to create innovative building materials could be a solution to reduce the environmental impact and to limit the waste disposal costs. The use of chitosan as a natural binder was investigated in order to obtain more easily recyclable materials with a lower environmental impact. The physical and thermal performances were tested, studying the correlation between porosity and thermal parameters. The experimental thermal conductivity range was between 0.049 and 0.06 W·m-1 ·K-1. Results proved the possibility to produce sustainable thermal insulation materials with performances comparable to conventional building products. Heat transfer through fibrous materials involves combined modes of heat transfer (conduction, convection, radiation) through the different phases (solid and gas): conduction in the solid and gas phase, and convection and radiative transfer through the gas phase. This paper focuses on the development and validation of a physical model for effective thermal conductivity in highly porous fibrous materials like wool panels with natural binder. If compared to the models currently available in the literature, the proposed model shows an improved correlation with the experimental data for the materials of interest.

Analysis of Sheep Wool-Based Composites for Building Insulation

“…Guna et al [ 20 ] studied wool–polypropylene panels with λ values between 0.058 and 0.083 W/mK. Rubino et al [ 19 ], for wool–chitosan samples, obtained λ values of 0.049–0.060 W/mK.…”

“… Thermal conductivity of samples; values of this study correspond to the minimum and maximum values recorded (data from refs. [ 17 , 19 , 20 , 40 , 50 ]). …”

“…The product obtained by combining thermal and chemical methods for the partial degradation of fibres in order to obtain a protein-based adhesive that sticks the remaining fibres, was presented in [ 18 ]. The use of wool textile waste by preparing a composite thermal insulation material in which the textile fibres are bonded with a chitosan solution was presented by Rubino et al [ 19 ]. The preparation of wool and polypropylene fibre composites, by carding the two types of fibres, followed by hot pressing of the mixture, was presented by Guna et al [ 20 ].…”

Wool waste used as sustainable nonwoven for building applications

“…The measurement results of BICO samples were finally compared with innovative materials obtained by binding similar 100% wool waste fibers with chitosan and gum Arabic solutions. Chitosan and gum Arabic based wool samples (respectively referred as CH and GA samples), whose thermal and acoustic behaviour were widely discussed in previously published works (Rubino et al, 2019a;2019b), were further investigated in terms of hygric performances. The aim was to analyze the possible effects of the thermal and chemical manufactured process on the hygrothermal, acoustic and non-acoustic properties of the final nonwoven composites.…”

“…Several samples with different bulk density values were manufactured and their hygrothermal and acoustic performances were tested. Finally, the experimental results were used to compare physical properties among different innovative materials previously tested (Rubino et al, 2019a;2019b). The materials chosen for comparison were prepared using chitosan and gum Arabic binders to bond 100% wool waste fibers.…”